Iseikonic spectacles and their manufacture



May 24, 1938. A. F. DHTMEFL 2,118,173

v ISEIKONIC SPECTACLES AND THEIR MANUFACTURE vFiled oct. 1a, 1934 17 sheets-sheet 1 o' Pfl )vly I E y@ @Q/ EQ/ i -ff/X 'X" -oseljf ae@ @fg/1%@ May 24, 1938. A. F. D'ITTMER 2,118,173 ISEIKONIQ SPECTACLES AND THEIR-MANUFCTURE *I Fild oct. 1s, 1934 lvsheets-sheet 2 May 24, 1938. A. F. DITTMER 2,118,173

A l ISEIKONIC SPECTACLES AND THEIR MANUFACTURE Filed Oct. 18,' 1954 17 Sheets-Sheet 5 EYE @ ,/H' /fff f H ,WAK

May 24, l1931s. A, Dn-TMR 2,118,113

ISEIKONIC SPECTACLES AND THEIR MANUFACTURE Filed Oct. 18, 1934 17 Sheets-Sheet 4 Arthur j? a'ttmer( May 24, 1938. A. F. DITTMER 2,118,173

ISEIKONIC SPECTACLES AND THEIR MANUFACTURE Filed oct. 18, 1954 17 sheets-Sheet 5- I 0" 30 /aa 0.70 60 J0 40 30 20/ m20 30l '4a .Ja 60706 'May 24, 1938. A. F. lam-MERA 2,113,173

ISEIKONIC SPECTACLES AND THEIR MANUFACTURE Filed oct. 1s, 19:54 17 sheets-sheet ves laval/'@7120 7 'May 24, 1938. A. F. DWTMER 2,118,113

ISEIKONIC SPECTACLES AND THEIR MANUFACTURE Filed Oct. 18, 1934 17 Sheets-Sheet 7 May 24, 1938. A. F. lDrrTMERV ISEIKONIC SPECTACLES AND THEIR MANUFACTURE Filed oct. 1s, 19:541

17 Sheets-Sheet 8 MW w May 24, 1938. A. F. DITTMER ISEIKONIC SPECTACLES AND THEIR MANUFACTURE Filed Oct. 18,'1934 17 Sheets-Sheet 10 May 24, 1938. A E .TTMER Y 2,118,173

. I'SEIKONIC SPECTACLES AND THEIR MANUFACTURE May 24, 1938. A F' DH1-MER 2,118,173

ISEIKONIC SPECTACLES AND THEIR MANUFACTURE Filed Oct. 18, 1934 17 Sheets-Sheet 13 (72 73J 74 dif n 1761997376071' A'tz ur z't/mer l ,MM AM M @Qi/254 May 24, 1938- A. F. Dl'r'rMl-:R 2,118,173

ISEIKONIC SPECTACLES AND THIR MANUFACTURE Filed oct. 18, 1934 17 sheets-sheet 14 Ufff/4M Ms 22 4.50 5:40006: M1?.

May 24, 1938.

A. F. DITTMER v IsEIKoNlC SPECTACLES AND THEIR MANUFACTURE Filed Oct. 18, 1934 1'7 Sheets-Sheet 15 May 24, 1938.

A. F. DITTM ER ISEIKONIC SPECTACLES 'AND THEIR MANUFACTURE Filed Oct. 18, 1934 17 Sheets-Sheet 16 May 24, 1938H A. F. DITTMER ISEIKONIC SPECTACLES AND THEIR MANUFACTURE AFiled Oct. 1s, 1934 17 Smets-sheet 17 NQYMWN i Patented May 24, 1938 UNITED STATES 'PATENT ori-ics KSEIKONIC SPECTACLES AND THEIR MANEJ- FAC TURE

Application October 18,

16 Claims.

The human eyes are subject to refractory defects which can be corrected by the well known eyeglasses prescribed for this purpose, and in addition to defects involving differences in the size and/or shape of the ocular images, which may be described as the impressions formed in the higher brain centers through the vision of each eye, and are determined not only by the properties of the dioptric images that are formed on the retinas of the eyes, but also by the modifica-- tions imposed upon those images bythe anatomical properties and physiological processes which carry them to these centers.

Herein, the conditions which have to do with .i differences in the size and/or shape of the ocular images will be called eikonic conditions. The

condition in which the size and shape of the ocular images of a person are equal will be referred to as iseikonia, whereas the condition 2 in which the size and/or shape of the ocular images are unequal will be termed aniseikonia.

As explained in Letters Patent No. 1,933,578, of November '7, 1933, to Adelbert Ames, Jr. and Gordon' H. Gliddon, aniseikonia may not only impair binocular vision, but also the general well being of the person having such defects, and glasses eliminating or at least alleviating aniseikonia, or iseikonic lenses, are described and claimed in this patent. As also pointed out in 30 the aforesaid patent, the ratio of Aocular images may be the same in all meridians (overall aniseikonia) or it may be symmetrical to one meridian (meridional aniseikonia). The ocular image differences may also be quite irregular and unsymmetrical, in which case they are referred to as ocular image shape differences. Herein, all three types of ocular image differences will be shortly referred to as aniseikonia, unless it is specifically stated that only one of these several types of differences (which may, and often are, coexistent) is discussed in any particular instance, when they will be termed overall, meridional and irregular aniseikonias, respectively.

In many cases, aniseikonia is co-existent with refractive defects and is often partly or wholly caused by these defects and/or the means effecting corrections thereof. Therefore, refractive defects and eikonic differences must be correlated for optimum correction. For this purpose com- ;,0- bined iseikonic lenses, as described in the aforementioned patent. with one element correcting all refractive defects and a superposed lens correcting only image differencesI (inherent and/or introduced by the refractory correction) can be worn. These, however, areoften cumbersome 1934, serial No. 748,788 (o1. iss-54) and are also unsightly and hard toV clean. The y said patent, therefore, also contemplates the use of single lenses effecting all necessary corrections, and of lens combinations, where four surfaces cooperate in correcting the defects, whereas any lens element alone does not have any specific function, as for example size correction only. In the very large majority of cases, it is possible to compute and to manufacture spectacles with lenses of this typ'e which are not unduly different from the customary eyeglasses, nor too heavy, or otherwise inconvenient. However, the computation of such lenses could heretofore only be carried out by haphazard and ve`ry tedious methods, mainly by trial and error, which made the procedure diiiicult and expensive. Therefore, the, for obvious reasons desirable, widespread use of the new and very beneficial spectacles, necessarily based on a commercial supply of prescriptions and of the eyeglasses themselves, was severely handicapped not only by excessive cost but also by the difficulty of securing persons trained and able to make the necessary involved and lengthy calculations.

Also, the lenses cited in the aforementioned patent were contemplated to correct overall and meridional aniseikonia only. In many cases there also exist irregular size differences and differences in the angular position of lines in the ocular images which may in many cases be of such magnitude as to be very injurious to the patient. In these cases it is in general not possible completely to correct all the differences with practical eyeglasses. It is however, possible to nd the best practical eyeglasses which will substantially correct some of the diilerences, and partially correct the others, the choice as to which differences are to be wholly corrected, and which are to be only partially corrected being largely determined by known facts regarding the relative importance of these differences in the functioning of the eyes in binocular vision.

It is, therefore, the main object of the present invention to provide practical eyeglasses, that s eyeglasses that can be practically computed, manufactured and worn, for the correction of all types of refractive defects and eikonic differences, which substantially correct the defects and diierences found and measured when `testing the eyes, and to provide methods for quickly,

These and other objects, aspects and features will be apparent from the following detailed explanations of the invention which refer to drawings in which:

Fig. l is a diagrammatical representation of one of the tests upon which the present invention is based;

Fig. 2 is a diagram showing the appearance of the eikonic test target with fused binocular vision when only an overall size difference is present;

Fig. 3 is a diagram similar to Fig. 2 showing the appearance when a simple type of meridional size difference is present;

Fig. 4 is a diagram similar to Fig. 2 showing the appearance when only an overall angular difference is present;

Fig. 5 is a diagram similar to Fig. 2 showing the appearance when an irregular angular difference is present;

Fig. 6 is a diagram similar to Fig. 2 showing the appearance when both an irregular size and an irregular angular difference are present;

Fig. 7 is a schematical View of the opthalmoeikonometer testing means before each eye;

Fig. 8 is a diagram explaining the notation of size difference;

Fig. 9 is a diagram explaining some of the terms used in the present description.;

Fig. 10 is a diagram explaining the conditions which must be fulfilled in or'der to correct the measured refractive defects; 4 y

Fig. 11 is a diagram explaining the conditions which must be fulfilled in order to correct the measured defects in size and/or shape;

Figs. 12 and'12a are diagrams explaining some of the terms used in the present description;

Fig. 13 is a diagram explaining the general conditions of equivalence for parallel principal meridians; v

Figs. 14 and 15 show nomographic diagrams employed for purposes of this invention;

Fig. 16 shows superimposed diagrams Figs. 14 and Fig. 17 is a diagram explaining the nomographic diagram shown in Fig. 16;

Fig. 18 is another nomographic diagram em.- V

ployed for purposes of the present invention;

Fig. 19 is a diagram somewhat similar to Fig. 9;

Fig. 20 is part of a so-called A chart; for lenses of type (1);

Figs. 21 and 22 .are tables explaining the A chart part of which is shown in Fig. 20;

Fig. 23 is part of a so-called B chartfor lenses of type C);

Figs. 24 and 25 are tables similar to Figs. 21rand 22, explaining the A and B charts for lenses of type (2);

Fig. 26 is a diagram showing lenses of type (1) Fig. 27 is a diagram showing lenses of type (2) Fig. 28 is a diagram showing lenses of type (3) Fig. 29 is a diagram showing lenses of types (4) and (5);

Figs. 30 and 31 are tables similar to Figs. 21 and 22, explaining the A and B charts for lenses of types (3), (4) and (5);

Fig. 32 is a part of the A chart for lenses of type (4) Fig. 33 is a part of the B chart forlenses of type (4);

Figs. 34 and 35 show, in top and sectional views respectively, the manner in which the A and B charts are preferably mounted for use;

Figs. 36 and 37 are charts used in connection with the A chart for lens'es of type (4);

Fig. 38 is a diagram of a special interpolation ruler used with the A and B charts;

Fig. 39 is a table giving the specifications of a particular lens of type (4);

Fig. 40 is a chart for obtaining modified y values;

Fig. 41 is a chart for obtainingmodified LM values;

Fig. 42 is a flow diagram explaining the method according to the present invention; and

Figs. 43 and 44 show spectacle lensesaccording to my invention with inserts, and inserts and slipover lenses, respectively.

The refractive defects and eikonic differences to be corrected with eyeglasses of the type above discussed are detected and their magnitude determined with instruments as for example described in Letters Patent No. 1,944,871, of January 30, 1934, to Adelbert Ames, Jr. and Gordon H. Gliddon, No. 1,946,925, of February 20, 1934, to Adelbert Ames, Jr. No. 2,063,015 of Deo. 8, 1936 and No. 2,095,235 of Oct. 12, 1937. These instruments, called ophthalmo-eikonometers, yield test data which measure the defects and differences present, that is, the ordinary and astigmatl'c refractive defects as measured by spherical and cylindrical dioptric test lenses with the aid of dioptric test targets, and the eikonic differences present, after correction of the refractive defects vwith the dioptric test lenses, as measured by suitable iseikonic test lenses with the aid of the peculiar test targets described in the above-identherefore fusible fixation objects fl and fr, and

dissimilar non-fusible test patterns pl and pr which, however, are arranged similar with respect to their fixation objects. In fused binocu-` lar vision, the appearance of the test patterns relative to each other and to the fused fixation object permits exact determination of the eikonic differences present, and controlled measurement thereof. For example if LR of Fig. 1 is the appearance of the test means after application of the dioptric lenses which correct the refractive errors and suitable iseikonic test lenses to equalize the size and/or shape of the ocular images, equality of distance al and ar, and bl and br,

respectively, indicates that the image size diierences have been completely eliminated in the horizontal and vertical meridians. The gure also shows that image size differences have been Fig. 3 shows the appearance when a simple type of meridional aniseikonia is present. In this case the image seen by the right eye is larger than that seen bythe left eye in the vertical meridian. In the forty-five degree (45) and one hundred and thirty-five degree (135) meridians the difference is made up of a difference in the size of the images and a difference in the angular position of lines connecting the similarly placed test objects.

Fig. 4 shows the appearance when an overall angular difference is present.

Fig. shows the. appearance when an irregular angular difference is present.

Fig. 6 shows the appearance when both irregu- -lar size differences and irregular angular differences are present.

This ophthalmo-eikonometer measurement is accomplished with the aid of lenses having vergence power (this term being employed to designate the effect of changing the image distance) in all meridians and in selected meridians of astigmatism (of the same or different inclination for both eyes), lenses without power which change the size in all meridians and in selected meridians, and lenses without power which change the relative angular positioning of the ocular images of any selected meridian.

Generally speaking, there will be placed in front of each eye dioptric test lens I, for spherical refractive correction, and dioptric test lens 2 for astigmatic correction as indicated in Fig. 7, supported in a holder as shown in the abovementioned Patent No. 2,095,235. There will be further a calibrated lens system 3 for changing the overall size of the ocular image and a calibrated lens system 4 for changing the size of the ocular image in a single meridian but leaving the size unchanged in the meridian ninety v degrees (90) removed from that single meridian. Systems 3 and 4 may be elements of trial sets comprising stepped glasses effecting known changes of image size, or, preferably, they are lens sets for the continuous change of image size without change of power (also called adjustable iseikonic lenses), as describedand claimed in the copendlng application Serial No. 713,701, led March 2, 1934, and they-are so indicated in Fig. '7. There will also be test lens or lenses 5. These are'lenses without power which change the size in a single meridian by a fairly large amount, e. g. four per cent (4%) leaving the size ln the meridian ninety degrees (90) removed unchanged or at most very slightly changed. These lenses are used to measure the angular differences of the ocular images in the following manner. They are mounted so as to be free to rotate about their optic axes. If it is desired to measure the angular difference in any single meridian, e. g. the horizontal meridian, the test lens 5 is rotated about its optic axis until a line joining the two dark spots Which are in the horizontal meridian of the eikonic target would appear parallel to a line joining the two light points in the horizontal meridian of the eikonic target. The amount of angular difference present after the refractive errors have been corrected with the dioptric test lenses can be found from the record of the axis setting of lens 5 necessary to correct it, by well known optical rules. If it is desired to measure the angular difference in any other meridian, a separate measurement is made with lens or lenses 5.

The angular difference may also be measured with the ophthalmo-eikonometer described in the above-identified Letters Patent No. 1,946,925, by rotating one of the eikonic targets until lines joining the non-fusible test objects in the meridian in which the difference is being measured would appear parallel in fused binocular vision. The amount of rotation, as read on the calibrated scale of the rotated target, necessary to make such lines appear parallel is then a measure of the angular difference in the meridian in which it is being measured. I

The angular difference measured by lens system 5 may be only the remainder after some or all of the size differences have been eliminated with lens systems 3 and '4. In general vthe axis setting of lens system 5 together with the known lens systems I, 2, 3, 4, before both eyes gives a measure of the angular difference present, as will be apparent from the following explanation referring to Fig. 8.

There may be in addition test lenses 6 and/or l and/or 8 taking care of special corrections, for example certain large steps of eikonic correction, (auxiliary iseikonic lenses) used to extend the range of the adjustable iseikonc lenses or certain small steps in dioptric correction, used to obtain smaller steps than are usually furnished in dioptric test sets. Since the use of these lenses is immaterial with regard to the following description, they will be omitted therefrom in order to simplify it.

Thus, after having examined the patient. the clinician has a measurement of the refractive defects of the patient in terms of dioptric test lenses l and 2, and measurements of the dilferences, both size and angular, of the ocular images in terms of lenses or lens systems 3, 4 and 5. It should be understood that a single setting of lens systems 3 and 4 may eliminate only the size differences in two meridians at right angles to each other, while a single setting of lens or lenses 5 may eliminate only the angular difference in a single meridian. Hence a complete measurement of a single patient may consist of more than one record of the settings of lenses 3 and 4, if that is necessary to eliminate the size differences in more than two meridians at right angles to one another, and more than one record of the setting of lens or lenses' 5 if that is necessary to eliminate the angular difference in all meridians.

Tests are made for distant Vision and for reading position. The test for distant vision is usually made with the fusible objects in the eikonic test target (or its image as formed by lenses) at a distance. of six meters (6 m.) from the eyes on a horizontal line which is perpendicular to and bisects the line joining the poles of the corneas of the patients eyes. The test for reading position is usually made with the fusible objects in the eikonic test target (or its image as formed by lenses) at a distance of forty centimeters (40 cms.) from the eyes on a line inclined twenty degrees (20) downward from the horizontal and which is perpendicular to and bisects the line joining the poles of the corneas of the patients eyes.

It is to be understood that the above means for detecting and measuring the refractive defects and eikonic differences are here given for pur poses of illustration only and that the method of quickly and easily providing practical eyeglasses which correct these measured refractive defects and eikonic differences as completely as possible is not restricted to these methods of measurement, but is applicable to any measurements of the refractive defects and the ocular image differences which may be available.

It should be kept in mind that the data of test lenses Iy and 2 signify a certain refractive defect and in addition an eikonic difference that may be introduced by the lens which corrects the refractive defect, and that the data of lenses 3, 4 and 5 ordinarily import only image size changes and angular changes which measure the inherent 

